Objective: Macrophage polarization is essential for immune homeostasis. In some studies, lymphagiogenesis has been suggested to be associated with macrophage polarization. The distribution and function of lymphatics in the maternal-fetal interface of preeclampsia (PE) during pregnancy has been reduced, and the macrophage in the decidua of PE has also been shifted to the M1 phenotype. The purpose of this study was to investigate the association between lymphatic endothelial cells and macrophage polarization in the maternal-fetal interface of normal and PE. Methods: The human primary decidual lymphatic endothelial cells (dLECs) was isolated from decidua of gestational age matched normal (n=5) and PE pregnancies (n=5). To investigate the difference of M1/M2 ratio, THP-1 derived M0 macrophages were cultured with dLECs or cell supernatant. Polarization of macrophages toward M1 or M2 was confirmed by expression of cell-surface markers in flow cytometry analysis (HLA-DR and CD80 for M1, CD163 and CD209 for M2). To investigate the factors associated with macrophage polarization, we assessed the relative gene expression profiles for normal versus PE dLECs by microarray. Results: When PE-dLECs or PE dLEC cell culture supernatant was added to M0 macrophage and cultured for 48hr, the M1/M2 ratio was increased compared to the normal group. Microarray analysis showed that GM-CSF expression was significantly higher in PE dLEC compared with normal. The levels of GM-CSF increased in PE dLEC cell supernatants collected after 48hr exposure compared to control. Conclusion: We think there is a close connection between lymphatic endothelial cell and macrophage polarization in the maternal-fetal interface.